Comparison of nasal and tracheobronchial clearance by similar techniques in normal subjects.

Nasal and tracheobronchial mucociliary clearance have been compared in 10 healthy subjects. Nasal clearance was measured by monitoring the rate of removal of 2 microns diameter Teflon particles, labelled with 99mTc, which had been placed in the anterior part of the nose. Tracheobronchial clearance was measured with an objective radioaerosol technique, 5 microns diameter polystyrene particles being used. With these comparable techniques there was a close correlation between the nasal mucociliary clearance rate and both the area under the tracheobronchial clearance curve from 0 to 6 hours after radioaerosol inhalation (rs = -0.94, p less than 0.001) and the area under the tracheobronchial clearance curve from 0 to 2.5 hours after inhalation (rs = -0.79, p less than 0.01). The rate of clearance of small particles from the nose may thus be a useful guide to tracheobronchial clearance in healthy individuals.